Stainless or factory exhaust manifolds, results inside.

[Boosted Zed]

Yes I know the one you mean. I sold one of these way back in 1998 and it was at Show and Shine yesterday.

[browny]

SK, I've seen you refer to that manifold in several posts and it sounds interesting. Do you have any pics so I can see what it actually looks like?

[Beer Baron]

just google GTS-R. oh f**k it. here you go mr lazy:

[Boosted Zed]

That is nice but custom not cast factory. Also single turbo different to twin turbo no room set up.

[Beer Baron]

too true, but that is a factory nissan manifold. it's the one gary was talking about that came on the few HR31 GTS-Rs that were built. it's a good point though with a single turbo set-up manifold design is freed up a lot. but if you are keeping the GTR twins then a extrusion honed and match ported factory manifold is the way to go. main reason I think is that the stainless ones are 1. expensive and 2. introduce a lot more heat into the engine bay which is not nice.

John, when I upgrade the turbos on the GTR if I stick with the twins you can whack the goo honed manifolds on.

[Boosted Zed]

Goo honed I like that. Go the goo. Also I thought the GRS-R stock manifolds are cast?

Those ones on the RACE car in pic are not cast and not standard, I would remember if they were like that. Maybe I need another V.

[Beer Baron]

maybe you are right and I need another beer? :confused:

I was sure that manifold came on the publically available HR31 GTS-Rs? hmmm I have been know to spin a bit of shit before. perhaps they were limited to the race cars. would make sense as it doesn't really look like a production version...

hmm well you have now convinced me that I'm wrong. I'm sure that's the one gary meant though, the old bunch-o'-bannanas.

[browny]

Hey I tried a search but i'm obviously not as good as you...

Know of any more pics, esp around the collector area?

[Beer Baron]

Hey I tried a search but i'm obviously not as good as you...

that is a fair excuse I suppose. not many people are.

as for more pics, all I did was typre in "HR31 GTS-R" into google and on one of those pages is a few pics. the car belongs to terry ashwood so I guess you could search for his name too and that would yield some results.

[browny]

Ahh, I tried R31 GTSR. You get a whole different set of results.

[lwells]

Personally I prefer the factory exhaust manifold, the best I have seen on an RB20/25DET was the factory Group A R31GTSR.  Now that's an exhaust manifold, all thick walled, equal volume, steel pipe that it is.

That's great if you have an RB20/25, but what about RB26 options (sorry, I'm feeling selfish today )

Extruded honing ... is effective when the component being honed is the weak link in the chain, but it is waste of time and money when there are other components negating the benefits (because they are the weak link in the chain).

When do the stock RB26 lowmount manifolds, in your estimation, become "the weak link"?

... the GTSR Group A exhaust manifold barely flows any more than the standard RB20DET exhaust manifold, but they make 25 rwkw extra. Why? Because of the extractor effect of the equal length primary pipes.

Given the above I would assume that when the lowmounts do become the weak link you would advocate for an equal length solution (assuming one fits in a road car engine bay) over extrude honing the stock manifolds?

Lucien.

[jaik]

Here are pics of the Nissan R31 GTS-R Group A Manifold or whatever the hell it is

http://www.skylinesaustralia.com/forums/at...achmentid=39945

http://www.skylinesaustralia.com/forums/at...achmentid=39946

JK

[Sydneykid]

The reason the GTSR exhaust manifolds work is because they are tuned length. At their tuned rpm they extract (accelerate) the exhaust gas flow into the turbine. The pulse from one cylinder travels down the pipe and as it passes the collector it creates a partial vacuum for the next cylinder to fire into.

I am sure if I thought about it long enough I could design the right length exhaust manifolds (two) for a GTR. All it would need is the firing order and the rpm. The volume of the pipe (length and/or diameter) determines the time (at the target rpm). The firing order is the tricky bit, 1-5-3-6-2-4. So it would need a long pipe from 1 and 3 and a short pipe from 2. And a long pipe from 4 and 6 and a short pipe from 5. Sounds just like the design of the standard GTR manifolds doesn't it?

[Guest DIRTgarage]

I may be willing to back to back test these once and for all.........donations please????

[Richard Everett]

Hi DOUGHBOY,

What was the result of the 'free of charge' testing?

Cheers,

Richard

[DoughBoy]

Haven't done anything about it, I need to get a couple of heads flowed so will toss the HKS manifolds in as well. Won't be for a month or so at the earliest.

[Guest Mashrock]

bump

[BOOSTD]

I'm running the chinese SS manifolds. Car made 360rwkw at 12 psi with GT2530's and ran the time below on 16psi... quite happy with them

[r33_racer]

We have a gcg ss manifold on the race car. It has been through 6 race meets and its cracked to the shithouse, I havent checked the primary runners wall thickness but everything was gusseted and welded pretty nice. Im a boily by trade so im pretty knowledgable on fab stuff. Now its cracked through the welds and around the haz around some of the welds and gussets. The welds had good penetration were the right colour and were several layers thick. Overall i was fairly impressed with the manifold in its construction. The biggest thing which everyone so far has seemed to miss is that stainless once its gone through alot of heat cycles goes brittle. Thats its biggest weakness. You can tell when ss has gone brittle when the colour of it goes dull grey, especially around the welds, a good weld should have a nice array of rainbow colours through it. If your manifold has grey/dark grey welds around it they are too hot and have compromised its grain sructure. Obviously after many shocks and vibrations and sudden jolts the brittle areas will crack as can be witnessed on our race car manifold.

I believe the ss manifolds do radiate more heat into the engine bay as ss absorbs alot of heat also and holds it extremely well. Our engine p.s loom is testament to that, melted wires everywhere, we didnt have that problem with the cast manifold with no shields on either. Weve gone through 2 silicone oil return hoses because of the radiating heat from the manifold, weve just changed everything over to teflon lined ss sheathed lines because of the massive heat issues were having.

Obviously on a race car the conditions are exaggerated immensely in comparison to a road car. Another boily i work with spent his time doing truck and car exhausts, and hes told me that on your average falcadoore you get about 3-4 years before the headers start to crack around the welds. Same problem different conditions, but nonetheless it still happens.